Microsoft has filed a 174-page brief asking the U.S. Court of Appeals to overturn the judgment of a District Court, which holds Redmond liable for $565 million USD in damages for violating a controversial patent held by Eolas.

The U.S. Patent and Trademark Office is currently re-examining the patent amid claims of "prior art" stemming from early HTML specification drafts authored by W3C chief Tim Berners-Lee and Dave Raggett. Microsoft has refrained from modifying its Internet Explorer Web browser, claiming that compliance with the court's ruling would "break" a multitude of third party Web sites and applications.

The trial has won Microsoft some support from an unlikely ally; the Electronic Frontier Foundation has launched a project to strike down dubious patents where prior art is said to exist and has zeroed in on Eolas in particular.

Due to the uncertainty that has grown out of the Eolas drama, a patch to comply with the injunction will not be included in Windows XP Service Pack 2. Microsoft also has some breathing room; the injunction has been stayed until the appeals court reaches a decision.

A short list of software potentially affected if Microsoft ends up on the losing end includes: Macromedia Flash, QuickTime, RealOne Player, Acrobat Reader, Sun's Java Virtual Machine, and Windows Media Player.